Leopold is extremely joyful to put up this vintage publication as a part of our broad vintage Library assortment. a number of the books in our assortment were out of print for many years, and for this reason haven't been available to most of the people. the purpose of our publishing application is to facilitate speedy entry to this sizeable reservoir of literature, and our view is this is an important literary paintings, which merits to be introduced again into print after many a long time.

RIGID BODY MOTION AROUND A FIXED AXIS that a sphere will "beat" a cylinder or a hoop down the same inclined plane, the hoop coming a poor third in the race. Problems 1. A flywheel of 10-ft diameter weighing 10 tons is making 40 rpm when thrown out of gear. In what time does it come to rest if the diameter of the shaft is 6 in. 05 (neglect spokes). 2. What is the moment of inertia in engineer's units of a flywheel which stores 200,000 ft-lb of kinetic energy when rotating 100 times per minute ? 3.

Since, initially, we have no clue as to GENERAL PLANE MOTION OF A RIGID BODY 41 what axis about which we should take moments let us select an axis at random through some point A. In general, the point A, so chosen, will itself be accelerated and its components of acceleration xa and ya are shown in the figure. | ^ > *i - * Λ — | FIG. II-2 The moment of the forces on m^ about A may now be written down by inspection of the figure. (We choose to take anticlockwise moments as positive following the usual convention.

T h e term ''inertial force" is used to designate these in order to distinguish them from the externally applied forces on the body. These inertial forces arise on account of the inertial behavior of the body in respect to its center of mass. NOTE ON THE INERTIAL FORCES 45 To sum up, in general, the equation of motion which describes the rotation of a body in plane motion is not simply LA = IAocA , but rather, LA - [MyA(x - xA) - MxA(y - yA)] = IA